As described in the related application, conventional rechargeable batteries may be arranged as small sets of batteries coupled to one or more conductors at either end of the sets of batteries, thereby coupling each set of batteries in parallel. The small sets of batteries may be coupled to one another in series to generate higher voltages than the voltages of the batteries themselves. The series-coupled sets of batteries may be provided in a single pack for ease of handling. However, it may be desirable to couple two or more of these packs to one another in series to generate higher voltages or in parallel to generate higher currents, or a combination of series and parallel couplings to achieve both a higher current and a higher voltage.
This inter-pack, series or parallel coupling can present various problems. For example, the related application described a geometry in which an odd number of smaller sets of parallel-connected batteries were arranged to allow connection via a u-shaped connector screwed into adjacent packs. However, this arrangement required the use of screws and bolts interior to the packs. The use of screws and bolts interior to the pack required extreme care to prevent dropping the screw or bolt into the pack, potentially shorting the batteries to one another. The screws could have been placed outside the packs to avoid the problems of dropping screws, however, access between the housings to get to the screws would have required space to be wasted.
Conventional wires or solid metal connectors may be used as conductors, as long as the wires or connectors have sufficient current carrying capacity. In a high-current environment, the wires or metal connectors must have sufficient thickness to carry the current required. However, with this thickness comes stiffness. In a high vibration environment, such as an electric or hybrid vehicle like a car or rocket, the wires or thick pieces of metal coupled to battery packs that are moving relative to one another as the vehicle flexes, could cause stresses on the metal conductors, the packs or the terminals connecting the packs to the wires or metal conductors. The stress could cause cracks in the conductors or the packs or cause a loosening at the terminals, and any or all of these things could lead to premature failure of the entire assembly, sparks, or changes to the electrical characteristics.
It can be desirable for any solution to have several properties. First, it can be desirable to keep connectors as short as possible. Short connectors keep the impedance of the connectors low, reducing losses and minimizing the electrical reaction of the connectors as changes occur in power supplied by the batteries. One potential solution towards keeping the conductors short is to use two sets of battery packs that “mirror” one another, allowing conductors to be placed back to back, for example, to reduce the length of the connectors that run between them. However, using different battery packs can increase the complexity of manufacturing and maintenance, as twice as many parts must be stocked and maintained as spares. Additionally, having mirror image battery packs may allow the wrong pack to be at least partially installed, requiring removal of the wrong pack and installation of the proper pack.
What is needed is a system and method that can allow for interconnections of battery packs, for example, with each pack containing multiple sets of parallel connected batteries, and each set connected in series, without placing screws or bolts interior to the packs, and without requiring space between each of the packs, and that can carry large amounts of currents in a high vibration environment, without damaging the packs or the interconnections, and without inducing stresses that would loosen the connections between the interconnecting conductors and the packs, cause sparks or change the electrical characteristics, without requiring lengthy interconnections, and without requiring mirror image battery packs.